In recent years, electronic devices, such as mobile phones, etc., have become equipped with a measuring device, such as a location identification unit using a GPS (Global Positioning System), etc., and an atmospheric-pressure sensor for measuring an atmospheric pressure, etc.
For these devices, there are demands for identifying an altitude of the current place and a floor number of a building using the atmospheric-pressure sensor. However, atmospheric pressure is changing any time because of a change in the weather, and thus it is not possible to identify an altitude and a floor number in a building directly from a value of an atmospheric pressure (hereinafter referred to as an atmospheric pressure).
Accordingly, to date, the current altitude and a floor number of an electronic device have been identified by the following method.
That is to say, a dedicated atmospheric sensor is disposed at a reference location whose altitude is known in advance. And an electronic device obtains the current atmospheric pressure value of the dedicated atmospheric-pressure sensor through communication, and then obtains the difference between an atmospheric pressure value of an atmospheric-pressure sensor attached to the electronic device and the current atmospheric pressure value. Thereby, the altitude is obtained by calculating the difference in altitude from that at the reference location. In a related-art technique, in order to identify a floor number of a building, conversion processing from the obtained altitude to the floor number is performed in addition.
Japanese Laid-open Patent Publication No. 2001-245027 is an example of related art.